From 953a44b3fd61302e6b86d549109a718a001c9b3c Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Sun, 17 Oct 2021 14:30:33 +0200
Subject: Fix heap corruption bug due to bad initialization

---
 src/bootstrap/environment.c |  1 +
 src/bootstrap/gc.c          | 41 +++++++++++++++++++++++------------------
 src/bootstrap/main.c        |  2 +-
 3 files changed, 25 insertions(+), 19 deletions(-)

(limited to 'src')

diff --git a/src/bootstrap/environment.c b/src/bootstrap/environment.c
index 570c5d4..d5e954b 100644
--- a/src/bootstrap/environment.c
+++ b/src/bootstrap/environment.c
@@ -21,6 +21,7 @@ Environment *
 env_create(Environment *parent) {
     Environment *env = alloc_env();
     env->parent = parent;
+    env->marked = false;
     env->buf = NULL;
     env->size = 0;
     env->cap = ENV_BUF_CAP;
diff --git a/src/bootstrap/gc.c b/src/bootstrap/gc.c
index 381ab6b..5f023bc 100644
--- a/src/bootstrap/gc.c
+++ b/src/bootstrap/gc.c
@@ -35,13 +35,9 @@ typedef struct GC {
     ActiveEnvs active_envs;
 } GC;
 
-// FIXME: small value for testing purposes
-// #define GC_OBJS_CAP 1024 * 1024 * 10
-// #define GC_ROOTS_CAP 1024
-// #define GC_ENVS_CAP 1024 * 1024 * 2
 #define GC_OBJS_CAP  1024 * 1024
-#define GC_ROOTS_CAP 1024 * 1024
-#define GC_ENVS_CAP  1024 * 1024
+#define GC_ROOTS_CAP 1024
+#define GC_ENVS_CAP  1024 * 4
 
 static GC gc;
 
@@ -82,7 +78,8 @@ void
 push_active_env(Environment *env) {
     if (gc.active_envs.size == gc.active_envs.cap) {
         gc.active_envs.cap *= 2;
-        gc.active_envs.buf = realloc(gc.active_envs.buf, gc.active_envs.cap * sizeof(Environment *));
+        gc.active_envs.buf = realloc(gc.active_envs.buf,
+                gc.active_envs.cap * sizeof(Environment *));
     }
     gc.active_envs.buf[gc.active_envs.size++] = env;
 }
@@ -148,9 +145,9 @@ mark_environment(Environment *env) {
     }
     env->marked = true;
     for (size_t i = 0; i < env->size; i++) {
-        EnvEntry entry = env->buf[i];
-        mark_obj(entry.symbol);
-        mark_obj(entry.value);
+        EnvEntry *entry = &env->buf[i];
+        mark_obj(entry->symbol);
+        mark_obj(entry->value);
     }
 }
 
@@ -177,11 +174,7 @@ mark_and_sweep(void) {
     for (size_t i = 0; i < gc.active_envs.size; i++) {
         mark_environment(gc.active_envs.buf[i]);
     }
-
     for (size_t i = 0; i < gc.roots.size; i++) {
-        if (gc.roots.buf[i]->marked) {
-            continue;
-        }
         mark_obj(gc.roots.buf[i]);
     }
 
@@ -231,8 +224,7 @@ dump_gc(void) {
             display(gc.roots.buf[i]);
             printf("\n");
         }
-        printf("------------- OBJECTS ------------- \n");
-        // for (size_t i = 0; i < gc.obj_cap; i++) {
+        printf("--------- OBJECTS (TOP 20) -------- \n");
         for (size_t i = 0; i < 20; i++) {
             printf("i: %ld -> ", i);
             Object *obj = &gc.objects[i];
@@ -249,8 +241,20 @@ dump_gc(void) {
             }
             printf("\n");
         }
-        printf("FREE OBJECTS: %ld\n", gc.free_objects.size);
-        printf("ENVIRONMENTS: %ld\n", gc.envs.size);
+        printf("-------------- MISC --------------- \n");
+        printf("gc.roots.size: %ld\n", gc.roots.size);
+        printf("gc.roots.cap: %ld\n", gc.roots.cap);
+        printf("gc.active_envs.size: %ld\n", gc.active_envs.size);
+        printf("gc.active_envs.cap: %ld\n", gc.active_envs.cap);
+        printf("gc.obj_cap: %ld\n", gc.obj_cap);
+        printf("gc.free_objects.size: %ld\n", gc.free_objects.size);
+        printf("gc.free_objects.cap: %ld\n", gc.free_objects.cap);
+        printf("gc.free_objects.position: %ld\n", gc.free_objects.position);
+        printf("gc.free_envs.size: %ld\n", gc.free_envs.size);
+        printf("gc.free_envs.cap: %ld\n", gc.free_envs.cap);
+        printf("gc.free_envs.position: %ld\n", gc.free_envs.position);
+        printf("gc.envs.size: %ld\n", gc.envs.size);
+        printf("gc.envs.cap: %ld\n", gc.envs.cap);
 }
 
 Object *
@@ -278,5 +282,6 @@ alloc_object(ObjectType type) {
     gc.free_objects.size--;
     Object *obj = get_obj(slot);
     obj->type = type;
+    obj->marked = false;
     return obj;
 }
diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index 7251e60..bf2354b 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -115,10 +115,10 @@ process_source(const StringView *source) {
         size_t root_stack_size = gc.roots.size;
         Object *root = parse_tree(&visitor);
         gc.roots.size = root_stack_size;
-        push_root(root);
         if (root == obj_err || errors_n != 0) {
             break;
         }
+        push_root(root);
 
         Object *result = eval(global_env, root);
         if (result != obj_nil) {
-- 
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